Schizophrenia susceptibility genes directly implicated in the life cycles of pathogens: cytomegalovirus, influenza, herpes simplex, rubella, and Toxoplasma gondii

Decoding the Nectin Interactome: Implications for Brain Development, Plasticity, and Neurological Disorders

The nectin family of cell adhesion molecules (CAMs) comprising nectins and nectin-like molecules has emerged as a key regulator of various pivotal neural processes, including neuronal development, migration, synapse formation, and plasticity. Nectins engage in homophilic and heterophilic interactions to mediate cell-cell adhesion, contributing to the establishment and maintenance of neural circuits. Their extracellular domains facilitate trans-synaptic interactions, while intracellular domains participate in signaling cascades influencing cytoskeletal dynamics and synaptic function. The exhibition of distinct localization patterns in neurons, astrocytes, and the blood-brain barrier underscores their diverse roles in the brain. The dysregulation of nectins has been implicated in several neurological disorders, such as neurodevelopmental disorders, depression, schizophrenia, and Alzheimer's disease. This review examines the structural and functional characteristics of nectins and their distribution and molecular mechanisms governing neural connectivity and cognition. It further discusses experimental studies unraveling nectin-mediated pathophysiology and potential therapeutic interventions targeting nectin-related pathways. Collectively, this comprehensive analysis highlights the significance of nectins in brain development, function, and disorders, paving the way for future research directions and clinical implications.

Serum signature of antibodies to Toxoplasma gondii, rubella virus, and cytomegalovirus in females with bipolar disorder: A cross-sectional study

BACKGROUND AND AIM

Immunity alterations have been observed in bipolar disorder (BD). However, whether serum positivity of antibodies to Toxoplasma gondii (T gondii), rubella, and cytomegalovirus (CMV) shared clinical relevance with BD, remains controversial. This study aimed to investigate this association.

METHODS

Antibody seropositivity of IgM and IgG to T gondii, rubella virus, and CMV of females with BD and controls was extracted based on medical records from January 2018 to January 2023. Family history, type of BD, onset age, and psychotic symptom history were also collected.

RESULTS

585 individuals with BD and 800 healthy controls were involved. Individuals with BD revealed a lower positive rate of T gondii IgG in the 10-20 aged group (OR = 0.10), and a higher positive rate of rubella IgG in the 10-20 (OR = 5.44) and 20-30 aged group (OR = 3.15). BD with family history preferred a higher positive rate of T gondii IgG (OR = 24.00). Type-I BD owned a decreased positive rate of rubella IgG (OR = 0.37) and an elevated positive rate of CMV IgG (OR = 2.12) compared to type-II BD, while BD with early onset showed contrast results compared to BD without early onset (Rubella IgG, OR = 2.54; CMV IgG, OR = 0.26). BD with psychotic symptom history displayed a lower positive rate of rubella IgG (OR = 0.50).

LIMITATIONS

Absence of male evidence and control of socioeconomic status and environmental exposure.

CONCLUSIONS

Differential antibody seropositive rates of T gondii, rubella, and cytomegalovirus in BD were observed.

Network-based drug repurposing for schizophrenia

Despite recent progress, the challenges in drug discovery for schizophrenia persist. However, computational drug repurposing has gained popularity as it leverages the wealth of expanding biomedical databases. Network analyses provide a comprehensive understanding of transcription factor (TF) regulatory effects through gene regulatory networks, which capture the interactions between TFs and target genes by integrating various lines of evidence. Using the PANDA algorithm, we examined the topological variances in TF-gene regulatory networks between individuals with schizophrenia and healthy controls. This algorithm incorporates binding motifs, protein interactions, and gene co-expression data. To identify these differences, we subtracted the edge weights of the healthy control network from those of the schizophrenia network. The resulting differential network was then analysed using the CLUEreg tool in the GRAND database. This tool employs differential network signatures to identify drugs that potentially target the gene signature associated with the disease. Our analysis utilised a large RNA-seq dataset comprising 532 post-mortem brain samples from the CommonMind project. We constructed co-expression gene regulatory networks for both schizophrenia cases and healthy control subjects, incorporating 15,831 genes and 413 overlapping TFs. Through drug repurposing, we identified 18 promising candidates for repurposing as potential treatments for schizophrenia. The analysis of TF-gene regulatory networks revealed that the TFs in schizophrenia predominantly regulate pathways associated with energy metabolism, immune response, cell adhesion, and thyroid hormone signalling. These pathways represent significant targets for therapeutic intervention. The identified drug repurposing candidates likely act through TF-targeted pathways. These promising candidates, particularly those with preclinical evidence such as rimonabant and kaempferol, warrant further investigation into their potential mechanisms of action and efficacy in alleviating the symptoms of schizophrenia.

Genetic causal association between varicella-zoster virus infection and psychiatric disorders: A 2-sample Mendelian randomization study

BACKGROUND

Psychiatric disorders, such as schizophrenia (SCZ), major depressive (MDD), and bipolar disorder (BD) have a profound impact on millions of individuals worldwide. The critical step toward developing effective preventive and treatment strategies lies in comprehending the causal mechanisms behind these diseases and identifying modifiable risk factors associated with them.

METHODS

In this study, we conducted a 2-sample Mendelian randomization analysis to explore the potential links between chickenpox(varicella-zoster virus infection) and three major psychiatric disorders(SCZ, MDD, BD).

RESULTS

In our MR study, among the three major psychiatric disorders, chickenpox was shown to be causally related to BD, indicating that infection with chickenpox may increase the risk of developing BD (IVW: OR = 1.064, 95% CI =1.025-1.104, P=0.001; RAPS: OR=1.066, 95% CI=1.024-1.110, P=0.002), while there was no causal relationship between SCZ and MDD. Similar estimated causal effects were observed consistently across the various MR models. The robustness of the identified causal relationship between chickenpox and BD holds true regardless of the statistical methods employed, as confirmed by extensive sensitivity analyses that address violations in model assumptions. The MR-Egger regression test failed to reveal any signs of directional pleiotropy (intercept = -0.042, standard error (SE) = 0.029, p = 0.236). Similarly, the MR-PRESSO analysis revealed no evidence of directional pleiotropy or outliers among the chickenpox-related instrumental variables (global test p = 0.653). Furthermore, a leave-one-out sensitivity analysis yielded consistent results, further underscoring the credibility and stability of the causal relationship.

CONCLUSIONS

Our findings provide compelling evidence of a causal effect of chickenpox on the risk of BD. To gain a more comprehensive understanding of this association and its underlying mechanisms, additional research is needed. Such investigations are pivotal in identifying effective interventions for promoting BD prevention.

Indicators of HSV1 Infection, ECM-Receptor Interaction, and Chromatin Modulation in a Nuclear Family with Schizophrenia

Schizophrenia (SCZ) is a complex psychiatric disorder with high heritability; identifying risk genes is essential for deciphering the disorder's pathogenesis and developing novel treatments. Using whole-exome sequencing, we screened for mutations within protein-coding sequences in a single family of patients with SCZ. In a pathway enrichment analysis, we found multiple transmitted variant genes associated with two KEGG pathways: herpes simplex virus 1 (HSV1) infection and the extracellular matrix (ECM)-receptor interaction. When searching for rare variants, six variants, SLC6A19p.L541R, CYP2E1p.T376S, NAT10p.E811D, N4BP1p.L7V, CBX2p.S520C, and ZNF460p.K190E, segregated with SCZ. A bioinformatic analysis showed that three of these mutated genes were associated with chromatin modulation. We found that HSV1 infection, ECM-receptor interaction pathways, and epigenetic mechanisms may contribute to the pathogenesis of SCZ in certain families. The identified polygenetic risk factors from the sample family provide distinctive underlying biological mechanisms of the pathophysiology of SCZ and may be useful in clinical practice and patient care.

Overview of Apoptosis, Autophagy, and Inflammatory Processes in Toxoplasma gondii Infected Cells

Toxoplasma gondii (T. gondii) is an obligate intracellular parasite. During the parasitic invasion, T. gondii creates a parasitophorous vacuole, which enables the modulation of cell functions, allowing its replication and host infection. It has effective strategies to escape the immune response and reach privileged immune sites and remain inactive in a controlled environment in tissue cysts. This current review presents the factors that affect host cells and the parasite, as well as changes in the immune system during host cell infection. The secretory organelles of T. gondii (dense granules, micronemes, and rhoptries) are responsible for these processes. They are involved with proteins secreted by micronemes and rhoptries (MIC, AMA, and RONs) that mediate the recognition and entry into host cells. Effector proteins (ROP and GRA) that modify the STAT signal or GTPases in immune cells determine their toxicity. Interference byhost autonomous cells during parasitic infection, gene expression, and production of microbicidal molecules such as reactive oxygen species (ROS) and nitric oxide (NO), result in the regulation of cell death. The high level of complexity in host cell mechanisms prevents cell death in its various pathways. Many of these abilities play an important role in escaping host immune responses, particularly by manipulating the expression of genes involved in apoptosis, necrosis, autophagy, and inflammation. Here we present recent works that define the mechanisms by which T. gondii interacts with these processes in infected host cells.

Maternal immune activation as an epidemiological risk factor for neurodevelopmental disorders: Considerations of timing, severity, individual differences, and sex in human and rodent studies

Epidemiological evidence suggests that one's risk of being diagnosed with a neurodevelopmental disorder (NDD)-such as autism, ADHD, or schizophrenia-increases significantly if their mother had a viral or bacterial infection during the first or second trimester of pregnancy. Despite this well-known data, little is known about how developing neural systems are perturbed by events such as early-life immune activation. One theory is that the maternal immune response disrupts neural processes important for typical fetal and postnatal development, which can subsequently result in specific and overlapping behavioral phenotypes in offspring, characteristic of NDDs. As such, rodent models of maternal immune activation (MIA) have been useful in elucidating neural mechanisms that may become dysregulated by MIA. This review will start with an up-to-date and in-depth, critical summary of epidemiological data in humans, examining the association between different types of MIA and NDD outcomes in offspring. Thereafter, we will summarize common rodent models of MIA and discuss their relevance to the human epidemiological data. Finally, we will highlight other factors that may interact with or impact MIA and its associated risk for NDDs, and emphasize the importance for researchers to consider these when designing future human and rodent studies. These points to consider include: the sex of the offspring, the developmental timing of the immune challenge, and other factors that may contribute to individual variability in neural and behavioral responses to MIA, such as genetics, parental age, the gut microbiome, prenatal stress, and placental buffering.

Infections and schizophrenia

This paper provides a critical review of the literature, demonstrating a certain pathogenetic role of various infections, primarily viruses from the herpes and chlamydia groups, in the development and progression of schizophrenia, including published results of the authors’ own long-term studies.

6 Weeks Monotherapy with Antipsychotic Drug Reduced Inflammatory Markers in Bipolar Disorder Patients

Bipolar Disorder (BD) is a mental disorder characterized by periods of depression and abnormally elevated moods. Recent studies proposed the existence of a correlation between inflammation, disease severity and response to antipsychotic therapy. The present study is aimed to investigate if treatment with second-generation antipsychotic, in monotherapy, influences the inflammatory process in BD patients. In 50 hospitalized BD patients who started monotherapy with second-generation antipsychotic, we investigated, after six-week of treatment, both clinical outcomes and change in inflammatory markers such as C-Reactive Protein (CRP) and Erythrocyte Sedimentation Rate (ESR). We observed a significant improvement of clinical symptoms (measured through MADRAS, YMRS, CGI and BPRS scales) in all treated patients. Moreover, we found that at the time of enrolment BD patients showed higher CRP levels compared to reference value, and that after 6 weeks of antipsychotic treatment CRP (but not ERS) plasma levels were significantly reduced returning to reference levels. The present exploratory study indicates that monotherapy with antipsychotic drugs reduces, not only BD symptoms, but also an inflammatory marker such as PCR. The evaluation of relationship between antipsychotic treatment and patients inflammatory conditions could be usefulness in clinical practice, both providing a marker to drug response, and permitting the identification of new targets in BD therapy.

A Preventive Role of RANTES Genetic Variation against Undifferentiated Schizophrenia

AIM

Due to conflicting data from relevant studies, evidence for chemokine alterations in the pathophysiology of schizophrenia (Scz) remains inconclusive. Thus, we aimed to investigate the impact of rs2107538, rs2280788, and rs2280789 polymorphisms in CCL5 gene, as well as rs333 within CCR5 gene and the development of Scz in a Tunisian cohort.

METHODS

We performed a case-control study composed of 200 patients and 200 controls using RFLP-PCR.

RESULTS

Among the analyzed polymorphisms, only rs2107538 imparted protection against Scz and more specifically to male sex. This protective effect remained valid for the undifferentiated form. Moreover, this SNP had an impact on patients' symptomatology. When focusing on haplotypes, we noticed that the rs2107538-rs2280788-rs2280789 ACT genetic combination, with only one mutated allele rs2107538A, displayed reduced frequency in both Scz (as a whole group) and undifferentiated subtype. The haplotype distribution profile implies that the A allele at rs2107538 could induce a protective effect by increasing RANTES production.

CONCLUSION

Additional independent analyses are required to corroborate these findings and elucidate the functional implications of the discovered preventing genotypes and haplotypes in Scz.

Cytomegalovirus Infection Associated with Smaller Total Cortical Surface Area in Schizophrenia Spectrum Disorders

OBJECTIVES

Cytomegalovirus (CMV) congenital infection and in immunodeficiency can have deleterious effects on human cortex. In immunocompetent adults, the putative association between CMV infection and cortical measures has not been explored. We hypothesized that CMV exposure is associated with smaller cortical surface area or cortical thinning mainly in patients with schizophrenia spectrum disorders.

STUDY DESIGN

We included 67 adult patients with schizophrenia spectrum disorders and 262 adult healthy controls. We measured circulating CMV IgG antibody concentrations with solid-phase immunoassay techniques. We measured the total cortical surface area, regional cortical surface areas and the overall mean cortical thickness based on T1-weighted MRI scans processed in FreeSurfer v6.0.

STUDY RESULTS

In the whole sample analysis, we found a significant diagnostic group-by-CMV status interaction on the total surface area (P = .020). Among patients, CMV antibody positivity was significantly associated with smaller total surface area (P = .002, partial eta2 = 0.138) whereas no such association was found in healthy controls (P = .059). Post hoc analysis among patients showed that higher CMV antibody concentrations were also significantly associated with smaller total surface area (P = .038), and that CMV antibody positivity was significantly inversely associated with 14 left and 16 right regional surface areas mainly in the frontal and temporal lobes. CMV infection was not associated with the overall mean cortical thickness.

CONCLUSIONS

The results are indicative of a cortical surface area vulnerability to CMV infection in patients with schizophrenia spectrum disorders but not in healthy controls. CMV infection may contribute to the established cortical surface area aberrations in schizophrenia.

Impact of SARS-CoV-2 on Host Factors Involved in Mental Disorders

COVID-19, caused by SARS-CoV-2, is a systemic illness due to its multiorgan effects in patients. The disease has a detrimental impact on respiratory and cardiovascular systems. One early symptom of infection is anosmia or lack of smell; this implicates the involvement of the olfactory bulb in COVID-19 disease and provides a route into the central nervous system. However, little is known about how SARS-CoV-2 affects neurological or psychological symptoms. SARS-CoV-2 exploits host receptors that converge on pathways that impact psychological symptoms. This systemic review discusses the ways involved by coronavirus infection and their impact on mental health disorders. We begin by briefly introducing the history of coronaviruses, followed by an overview of the essential proteins to viral entry. Then, we discuss the downstream effects of viral entry on host proteins. Finally, we review the literature on host factors that are known to play critical roles in neuropsychiatric symptoms and mental diseases and discuss how COVID-19 could impact mental health globally. Our review details the host factors and pathways involved in the cellular mechanisms, such as systemic inflammation, that play a significant role in the development of neuropsychological symptoms stemming from COVID-19 infection.

Emerging role and function of miR-198 in human health and diseases

Ever since their discovery, microRNAs (miRNAs/miRs) have astonished us by the plethora of processes they regulate, and thus adding another dimension to the gene regulation. They have been implicated in several diseases affecting cardiovascular, neurodegenerative, hepatic, autoimmune and inflammatory functions. A primate specific exonic miRNA, miR-198 has been vastly studied during the past decade, and shown to have a critical role in wound healing. The aberrant expression of miR-198 was first reported in schizophrenia, linking it to neural development. Later, its dysregulation and tumor suppressive role was reported in hepatocellular carcinoma. However, this was just a beginning, and after which there was an explosion of reports linking miR-198 deregulation to cancers and other ailments. The first target to be identified for miR-198 was Cyclin T1 in monocytes affecting HIV1 replication. Depending on the type of cancer, miR-198 has been shown to function either as a tumor suppressor or an oncomir. Interestingly, miR-198 is not only known to regulate multiple targets and pathways, but also is itself regulated by several circular RNAs and long-non-coding RNAs, highlighting a complex regulatory network. This review highlights the currently understood mechanism and regulation of miR-198 in different diseases, and its possible diagnostic and therapeutic potential.

Prolonged activation of cytomegalovirus early gene e1-promoter exclusively in neurons during infection of the developing cerebrum

The brain is the major target of congenital cytomegalovirus (CMV) infection. It is possible that neuron disorder in the developing brain is a critical factor in the development of neuropsychiatric diseases in later life. Previous studies using mouse model of murine CMV (MCMV) infection demonstrated that the viral early antigen (E1 as a product of e1 gene) persists in the postnatal neurons of the hippocampus (HP) and cerebral cortex (CX) after the disappearance of lytic infection from non-neuronal cells in the periventricular (PV) region. Furthermore, neuron-specific activation of the MCMV-e1-promoter (e1-pro) was found in the cerebrum of transgenic mice carrying the e1-pro-lacZ reporter construct. In this study, in order to elucidate the mechanisms of e1-pro activation in cerebral neurons during actual MCMV infection, we have generated the recombinant MCMV (rMCMV) carrying long e1-pro1373- or short e1-pro448-EGFP reporter constructs. The length of the former, 1373 nucleotides (nt), is similar to that of transgenic mice. rMCMVs and wild type MCMV did not significantly differed in terms of viral replication or E1 expression. rMCMV-infected mouse embryonic fibroblasts showed lytic infection and activation of both promoters, while virus-infected cerebral neurons in primary neuronal cultures demonstrated the non-lytic and persistent infection as well as the activation of e1-pro-1373, but not -448. In the rMCMV-infected postnatal cerebrum, lytic infection and the activation of both promoters were found in non-neuronal cells of the PV region until postnatal 8 days (P8), but these disappeared at P12, while the activation of e1-pro-1373, but not -448 appeared in HP and CX neurons at P8 and were prolonged exclusively in these neurons at P12, with preservation of the neuronal morphology. Therefore, e1-pro-448 is sufficient to activate E1 expression in non-neuronal cells, however, the upstream sequence from nt -449 to -1373 in e1-pro-1373 is supposed to work as an enhancer necessary for the neuron-specific activation of e1-pro, particularly around the second postnatal week. This unique activation of e1-pro in developing cerebral neurons may be an important factor in the neurodevelopmental disorders induced by congenital CMV infection.

Improving Therapeutic Interventions of Schizophrenia with Advances in Stem Cell Technology

Although historic documents posit schizophrenia to the beginnings of mankind, its diagnosis remains poorly defined, currently relying on unspecific clinical symptoms; and controversies still maintain its origin under intense debate. This review aimed at quantitatively assessing the preferential forefronts of clinical trials towards the treatment of schizophrenia from inception till present, according to clinicaltrials.gov database registry. Towards that end study status and study phase classifications were used as criteria for progress in the field. Study groups by sex and age together with countries and organisms involved in the studies were used as indicators of the populations studied and as evidence of main promoter institutions, in both, pharmacological and drug-free protocols. The findings clearly show a decline of active clinical research with small synthetic compounds and limited numbers of novel initiatives, mostly based on drug-free alternatives with expected reduced secondary effects. A paucity of sex- and age-oriented designs is detected, and it is proposed that future clinical trials should set their basis on data obtained from patient-derived induced pluripotent stem cells, brain organoid systems and human brain circuitry platforms. Only individual precision medical approaches may turn effective for the treatment of this complex and highly incapacitating disease.

Toxoplasmosis and Psychiatric and Neurological Disorders: A Step toward Understanding Parasite Pathogenesis

Toxoplasmosis, a disease that disrupts fetal brain development and severely affects the host's brain, has been linked to many behavioral and neurological disorders. There is growing interest in how a single-celled neurotropic parasite, Toxoplasma gondii, can control or change the behavior of the host as well as how it dominates the host's neurons. Secrets beyond these could be answered by decoding the Toxoplasma gondii genome, unravelling the function of genomic sequences, and exploring epigenetics and mRNAs alterations, as well as the postulated mechanisms contributing to various neurological and psychiatric symptoms caused by this parasite. Substantial efforts have been made to elucidate the action of T. gondii on host immunity and the biology of its infection. However, the available studies on the molecular aspects of toxoplasmosis that affect central nervous system (CNS) circuits remain limited, and much research is still needed on this interesting topic. In my opinion, this parasite is a gift for studying the biology of the nervous system and related diseases. We should utilize the unique features of Toxoplasma, such as its abilities to modulate brain physiology, for neurological studies or as a possible tool or approach to cure neurological disease.

Prior Toxoplasma Gondii Infection Ameliorates Liver Fibrosis Induced by Schistosoma Japonicum through Inhibiting Th2 Response and Improving Balance of Intestinal Flora in Mice

Schistosomiasis is an immunopathogenic disease in which a T helper (Th) cell type 2-like response plays vital roles. Hepatic fibrosis is its main pathologic manifestations, which is the leading cause of hepatic cirrhosis. Co-infections of Schistosoma japonicum (Sj) with other pathogens are frequently encountered but are easily ignored in clinical studies, and effective therapeutic interventions are lacking. In this study, we explored the effect of Toxoplasma gondii (Tg) prior infection on Th1/Th2 response, community shifts in gut microbiome (GM), and the pathogenesis of schistosomiasis in murine hosts. Mice were prior infected with Tg before Sj infection. The effects of co-infection on Th1/Th2 response and hepatic fibrosis were analyzed. Furthermore, we investigated this issue by sequencing 16S rRNA from fecal specimens to define the GM profiles during co-infection. Tg prior infection markedly reduced the granuloma size and collagen deposit in livers against Sj infection. Prior infection promoted a shift toward Th1 immune response instead of Th2. Furthermore, Tg infection promoted the expansion of preponderant flora and Clostridiaceae was identified as a feature marker in the GM of the co-infection group. Redundancy analysis (RDA)/canonical correspondence analysis (CCA) results showed that liver fibrosis, Th1/Th2 cytokines were significantly correlated (P < 0.05) with the GM compositions. Tg infection inhibits hepatic fibrosis by downregulating Th2 immune response against Sj infection, and further promotes the GM shifts through "gut-liver axis" in the murine hosts. Our study may provide insights into potential anti-fibrosis strategies in co-infection individuals.

NBIA: a network-based integrative analysis framework - applied to pathway analysis

With the explosion of high-throughput data, effective integrative analyses are needed to decipher the knowledge accumulated in biological databases. Existing meta-analysis approaches in systems biology often focus on hypothesis testing and neglect real expression changes, i.e. effect sizes, across independent studies. In addition, most integrative tools completely ignore the topological order of gene regulatory networks that hold key characteristics in understanding biological processes. Here we introduce a novel meta-analysis framework, Network-Based Integrative Analysis (NBIA), that transforms the challenging meta-analysis problem into a set of standard pathway analysis problems that have been solved efficiently. NBIA utilizes techniques from classical and modern meta-analysis, as well as a network-based analysis, in order to identify patterns of genes and networks that are consistently impacted across multiple studies. We assess the performance of NBIA by comparing it with nine meta-analysis approaches: Impact Analysis, GSA, and GSEA combined with classical meta-analysis methods (Fisher’s and the additive method), plus the three MetaPath approaches that employ multiple datasets. The 10 approaches have been tested on 1,737 samples from 27 expression datasets related to Alzheimer’s disease, acute myeloid leukemia (AML), and influenza. For all of the three diseases, NBIA consistently identifies biological pathways relevant to the underlying diseases while the other 9 methods fail to capture the key phenomena. The identified AML signature is also validated on a completely independent cohort of 167 AML patients. In this independent cohort, the proposed signature identifies two groups of patients that have significantly different survival profiles (Cox p-value 2 × 10⁻⁶). The NBIA framework will be included in the next release of BLMA Bioconductor package (http://bioconductor.org/packages/release/bioc/html/BLMA.html).

Maternal fatty acid concentrations and newborn DNA methylation

BACKGROUND

Preconception nutrition sets the stage for a healthy pregnancy. Maternal fatty acids (FAs) are related to beneficial neonatal outcomes with DNA methylation proposed as a mechanism; however, few studies have investigated this association and none with preconception FAs.

OBJECTIVES

We examined the relations of maternal plasma FA concentrations at preconception (n = 346) and 8 weeks of gestation (n = 374) with newborn DNA methylation.

METHODS

The Effects of Aspirin in Gestation and Reproduction Trial (2006-2012) randomly assigned women with previous pregnancy loss to low dose aspirin or placebo prior to conception. We measured maternal plasma phospholipid FA concentration at preconception (on average 4 mo before pregnancy) and 8 weeks of gestation. Cord blood DNA from singletons was measured using the MethylationEPIC BeadChip. We used robust linear regression to test the associations of FA concentration with methylation β-values of each CpG site, adjusting for estimated cell count using a cord blood reference, sample plate, maternal sociodemographic characteristics, cholesterol, infant sex, and epigenetic-derived ancestry. False discovery rate correction was used for multiple testing.

RESULTS

Mean ± SD concentrations of preconception marine (20:5n-3+22:6n-3+22:5n-3) and ω-6 PUFAs, SFAs, MUFAs, and trans FAs were 4.7 ± 1.2, 38.0 ± 2.0, 39.4 ± 1.8, 11.6 ± 1.1, and 1.0 ± 0.4 % of total FA, respectively; concentrations at 8 weeks of gestation were similar. Preconception marine PUFA concentration was associated with higher methylation at GRAMD2 (P = 1.1 × 10-8), LOXL1 (P = 5.5 × 10-8), SIK3 (P = 1.6 × 10-7), HTR1B (P = 1.9 × 10-7), and MCC (P = 2.1 × 10-7) genes. Preconception SFA concentration was associated with higher methylation at KIF25-AS1 and lower methylation at SLC39A14; other associations exhibited sensitivity to outliers. The trans FA concentration was related to lower methylation at 3 sites and higher methylation at 1 site. FAs at 8 weeks of gestation were largely unrelated to DNA methylation.

CONCLUSIONS

Maternal preconception FAs are related to newborn DNA methylation of specific CpG sites, highlighting the importance of examining nutritional exposures preconceptionally. This trial was registered at clinicaltrials.gov as NCT00467363.

Copy number variant syndromes are frequent in schizophrenia: Progressing towards a CNV-schizophrenia model

The genetic underpinnings of schizophrenia (SCZ) remain unclear. SCZ genetic studies thus far have only identified numerous single nucleotide polymorphisms with small effect sizes and a handful of copy number variants (CNVs). This study investigates the prevalence of well-characterized CNV syndromes and candidate CNVs within a cohort of 348 SCZ patients, and explores correlations to their phenotypic findings. There was an enrichment of syndromic CNVs in the cohort, as well as brain-related and immune pathway genes within the detected CNVs. SCZ patients with brain-related CNVs had increased CNV burden, neurodevelopmental features, and types of hallucinations. Based on these results, we propose a CNV-SCZ model wherein specific phenotypic profiles should be prioritized for CNV screening within the SCZ patient population.

Association between Toxoplasma gondii infection and psychiatric disorders in Zhejiang, Southeastern China

Increased rates of exposure to Toxoplasma gondii have been found in patients with psychiatric disorders globally, but there is scarce information about the epidemiology of T. gondii infection in psychiatric patients in Zhejiang Province, Southeastern China. In a case-control survey, we measured IgG and IgM class antibodies against T. gondii in 798 patients from a public psychiatric hospital in the city of Wenzhou, Zhejiang Province, and in 681 non-psychiatric controls from the general population in the same region. Subjects in each group were matched by sex and age with an enzyme-linked immunoassay. Seroprevalence of anti-Toxoplasma IgG antibodies in psychiatric patients (13.3%, 106/798) was significantly higher than in the control population (9.4%, 64/681) (P =  0.022). Anti-Toxoplasma IgM antibodies were also significantly higher in the psychiatric patients (4.1%, 33/798) than in the control group (1.9%, 13/681) (P =  0.016). Additionally, we found significantly elevated seropositive rates of anti-Toxoplasma IgG and IgM in patients with schizophrenia, as well as those with bipolar disorder. The identification of specific anti-Toxoplasma antibodies in psychiatric patients may be useful for assessing infection and timely initiation of treatment.

Comprehensive functional annotation of susceptibility SNPs prioritized 10 genes for schizophrenia

Nearly 95% of susceptibility SNPs identified by genome-wide association studies (GWASs) are located in non-coding regions, which causes a lot of difficulty in deciphering their biological functions on disease pathogenesis. Here, we aimed to conduct a comprehensive functional annotation for all the schizophrenia susceptibility loci obtained from GWASs. Considering varieties of epigenomic regulatory elements, we annotated all 22,688 acquired susceptibility SNPs according to their genomic positions to obtain functional SNPs. The comprehensive annotation indicated that these functional SNPs are broadly involved in diverse biological processes. Histone modification enrichment showed that H3K27ac, H3K36me3, H3K4me1, and H3K4me3 were related to the development of schizophrenia. Transcription factors (TFs) prediction, methylation quantitative trait loci (meQTL) analyses, expression quantitative trait loci (eQTL) analyses, and proteomic quantitative trait loci analyses (pQTL) identified 447 target protein-coding genes. Subsequently, differential expression analyses between schizophrenia cases and controls, nervous system phenotypes from mouse models, and protein-protein interaction with known schizophrenia-related pathways and genes were carried out with our target genes. We finaly prioritized 10 target genes for schizophrenia (CACNA1C, CLU, CSNK2B, GABBR1, GRIN2A, MAPK3, NOTCH4, SRR, TNF, and SYNGAP1). Our results may serve as an encyclopedia of schizophrenia susceptibility SNPs and offer holistic guides for post-GWAS functional experiments.

Comparison of the anti-inflammatory effect of aripiprazole and risperidone in 75 drug-naïve first episode psychosis individuals: A 3 months randomized study

INTRODUCTION

Evidence about the anti-inflammatory properties of antipsychotics has grown. However, no previous studies have compared the immunomodulatory effect of risperidone and aripiprazole.

OBJECTIVES

The main aim of the present work is to compare the anti-inflammatory effect of risperidone and aripiprazole on a large array of serum cytokines at 3 months following the onset of treatment.

METHODS

This is a prospective, randomized, open-label study. Patients were randomly assigned to risperidone or aripiprazole. From this randomization, 75 patients and 75 healthy volunteers that matched with the selected patients were picked for entry in this study. Serum concentrations of 21 cytokines/chemokines were measured at baseline and 3 months following the initiation of antipsychotic medication.

RESULTS

Those patients who were randomly assigned to risperidone had higher levels of IL-8 (p = 0.000) and MIP-1β (p = 0.007) than healthy volunteers at baseline, whereas no differences were found between patients initially assigned to aripiprazole and healthy volunteers. Three months following the onset of medication several cytokines decreased significantly: IL-8, MIP-1β, Fractalkine, TNF-α, IL-7, IL-13, IL-17α, IL-23, IL-21 (all ps < 0.01). No differences were found in the percentages of change between both treatments. The effect size of the two antipsychotics was similar, except for TNF-α, IL-13, IL-17α and Fractalkine, in which aripiprazole seems to have a greater effect size than risperidone, whereas risperidone seems to have a greater effect size than aripiprazole on MIP-1β.

CONCLUSIONS

This is the first study that has compared the immunomodulatory effect of risperidone and aripiprazole, finding that the anti-inflammatory effect of both treatments was similar.

Immune Responses Induced by HSP60 DNA Vaccine against Toxoplasma gondii Infection in Kunming Mice

Toxoplasma gondii can infect all the vertebrates including human, and leads to serious toxoplasmosis and considerable veterinary problems. T. gondii heat shock protein 60 (HSP60) is associated with the activation of antigen presenting cells by inducing initial immune responses and releasing inflammatory cytokines. It might be a potential DNA vaccine candidate for this parasite. A pVAX-HSP60 DNA vaccine was constructed and immune responses was evaluated in Kunming mice in this study. Our data indicated that the innate and adaptive immune responses was elicited by successive immunizations with pVAX-HSP60 DNA, showing apparent increases of CD3e+CD4+ and CD3e+CD8a+ T cells in spleen tissues of the HSP60 DNA-immunized mice (24.70±1.23% and 10.90±0.89%, P<0.05) and higher levels of specific antibodies in sera. Furthermore, the survival period of the immunized mice (10.53±4.78 day) were significantly prolonged during the acute T. gondii infection. Decrease of brain cysts was significant in the experimental group during the chronic infection (P<0.01). Taken together, TgHSP60 DNA can be as a vaccine candidate to prevent the acute and chronic T. gondii infections.

The Microbiome in Psychology and Cognitive Neuroscience

Psychology and microbiology make unlikely friends, but the past decade has witnessed striking bidirectional associations between intrinsic gut microbes and the brain, relationships with largely untested psychological implications. Although microbe-brain relationships are receiving a great deal of attention in biomedicine and neuroscience, psychologists have yet to join this journey. Here, we illustrate microbial associations with emotion, cognition, and social behavior. However, despite considerable enthusiasm and potential, technical and conceptual limitations including low statistical power and lack of mechanistic descriptions prevent a nuanced understanding of microbiome-brain-behavior relationships. Our goal is to describe microbial effects in domains of cognitive significance and the associated challenges to stimulate interdisciplinary research on the contribution of this hidden kingdom to psychological processes.

Are infectious agents involved in the pathogenesis of postpartum psychosis?

BACKGROUND

Since postpartum psychosis has been linked to activation of the immune system, it has been hypothesized that infectious agents may be involved in the pathogenesis of this disorder. We therefore investigated whether exposure to pathogens that can infect the central nervous system is increased in patients with postpartum psychosis.

METHODS

We measured the prevalence and titers of immunoglobulin G (IgG) and M (IgM) to herpes simplex virus type 1 (HSV-1) and 2 (HSV-2), Epstein-Barr virus (EBV), cytomegalovirus (CMV) and Toxoplasma Gondii (TG) in a cohort of patients with postpartum psychosis (n = 81) and compared these to matched postpartum controls.

RESULTS

We did not find significant differences in seroprevalence or antibody titers for any of these pathogens.

LIMITATIONS

Limitations of this study include the indirect measurement of infectious disease and the cross-sectional design.

CONCLUSION

Our results do not support the hypothesis that exposure to these neurotropic pathogens is involved in postpartum psychosis.

Maternal Immune Activation During the Third Trimester Is Associated with Neonatal Functional Connectivity of the Salience Network and Fetal to Toddler Behavior

Prenatal maternal immune activation (MIA) is associated with altered brain development and risk of psychiatric disorders in offspring. Translational human studies of MIA are few in number. Alterations of the salience network have been implicated in the pathogenesis of the same psychiatric disorders associated with MIA. If MIA is pathogenic, then associated abnormalities in the salience network should be detectable in neonates immediately after birth. We tested the hypothesis that third trimester MIA of adolescent women who are at risk for high stress and inflammation is associated with the strength of functional connectivity in the salience network of their neonate. Thirty-six women underwent blood draws to measure interleukin-6 (IL-6) and C-reactive protein (CRP) and electrocardiograms to measure fetal heart rate variability (FHRV) at 34-37 weeks gestation. Resting-state imaging data were acquired in the infants at 40-44 weeks postmenstrual age (PMA). Functional connectivity was measured from seeds placed in the anterior cingulate cortex and insula. Measures of cognitive development were obtained at 14 months PMA using the Bayley Scales of Infant and Toddler Development-Third Edition (BSID-III). Both sexes were studied. Regions in which the strength of the salience network correlated with maternal IL-6 or CRP levels included the medial prefrontal cortex, temporoparietal junction, and basal ganglia. Maternal CRP level correlated inversely with FHRV acquired at the same gestational age. Maternal CRP and IL-6 levels correlated positively with measures of cognitive development on the BSID-III. These results suggest that MIA is associated with short- and long-term influences on offspring brain and behavior.SIGNIFICANCE STATEMENT Preclinical studies in rodents and nonhuman primates and epidemiological studies in humans suggest that maternal immune activation (MIA) alters the development of brain circuitry and associated behaviors, placing offspring at risk for psychiatric illness. Consistent with preclinical findings, we show that maternal third trimester interleukin-6 and C-reactive protein levels are associated with neonatal functional connectivity and with both fetal and toddler behavior. MIA-related functional connectivity was localized to the salience, default mode, and frontoparietal networks, which have been implicated in the pathogenesis of psychiatric disorders. Our results suggest that MIA alters functional connectivity in the neonatal brain, that those alterations have consequences for cognition, and that these findings may provide pathogenetic links between preclinical and epidemiological studies associating MIA with psychiatric risk in offspring.

N-acetylgalactosaminyltransferases in cancer

Aberrant mucin-type O-glycosylation by glycosyltransferases is a well-described hallmark of many cancers and is also associated with additional non-cancerous developmental and metabolic disorders. The current review focuses on N-acetylgalactosaminyltransferase genes (GALNTs) and proteins (GalNAcTs) to illustrate their importance in cancer biology. Aberrant O-glycosylation by GalNAcTs activates a wide range of proteins that carry out interactions of sessile and motile cells affecting organogenesis, responses to agonists and stimulating hyperproliferation and metastatisation of neoplastic cells. As genome-wide analyses have provided abundant clues regarding under- or over-expressed genes that characterize different types of cancers, GALNTs and their transferase products have attracted attention by being unexpected actors in neoplastic contexts. We intend to review the current knowledge on GALNTs and their encoded transferases in cancer and suggest what could be the significance of such information in cancer pathogenesis and management.

Expression of schizophrenia biomarkers in extraocular muscles from patients with strabismus: an explanation for the link between exotropia and schizophrenia?

Recent studies have implicated exotropia as a risk factor for schizophrenia. We determined whether schizophrenia biomarkers have abnormal levels of expression in extraocular muscles from patients with strabismus and explored whether differences in gene expression between medial and lateral rectus muscles may explain the specific association of schizophrenia with exotropia but not esotropia. Samples from horizontal extraocular muscles were obtained during strabismus surgery and compared with age- and muscle type-matched normal muscles from organ donors. We used PCR arrays to identify differences in gene expression among 417 signaling molecules. We then focused on established schizophrenia-related growth factors, cytokines, and regulators of the extracellular matrix. Among 36 genes with significantly altered gene expression in dysfunctional horizontal rectus muscles, over one third were schizophrenia-related: CTGF, CXCR4, IL1B, IL10RA, MIF, MMP2, NPY1R, NRG1, NTRK2, SERPINA3, TIMP1, TIMP2, and TNF (adjusted p value ≤ 0.016667). By PCR array, expression of three of these genes was significantly different in medial rectus muscles, while eleven were significantly altered in lateral rectus muscles. Comparing baseline levels between muscle types, three schizophrenia-related genes (NPY1R, NTRK2, TIMP2) had lower levels of expression in medial rectus muscles. Despite the surprisingly large number of schizophrenia-related genes with altered gene expression levels in dysfunctional muscles, the lack of specificity for medial rectus muscles undermines a model of shared, region-specific gene expression abnormalities between exotropia and schizophrenia, but rather suggests consideration of the alternative model: that exotropia-induced aberrant early visual experiences may enable and/or contribute as a causative factor to the development of schizophrenia.

Toxoplasma gondii infection and schizophrenia: an inter-kingdom communication perspective

PURPOSE OF REVIEW

The apicomplexan protozoan Toxoplasma gondii has a striking predilection for infecting the central nervous system and has been suggested as a risk factor for schizophrenia. Here, we address some of the mechanisms by which T. gondii achieves this by manipulating signaling pathways of the host brain cells.

RECENT FINDINGS

Recent years have brought notable progress in the understanding of how the opportunistic parasite T. gondii establishes a successful infection in mammalian brain by secreting effector molecules that manipulate multiple cell functions. Many pathways involved in this inter-kingdom signaling, such as dopaminergic, GABAergic and kynurenine pathways, also have key roles in the development of schizophrenia. More understanding of T. gondii-brain cell interaction holds the key to unlocking the mystery of T. gondii-mediated schizophrenia pathogenesis.

SUMMARY

T. gondii usurps a variety of host signaling pathways to ensure physiological adaptation, evasion of host immune defense systems, and efficient replication. A detailed knowledge of T. gondii signaling molecules involved in this cross-kingdom communication with host brain cells will probably provide novel means of pharmacologically manipulating host cellular pathways to promote efficient elimination of the parasite and may permit the development of new schizophrenia-modifying therapeutics.

Our (Mother's) Mitochondria and Our Mind

Most of the energy we get to spend is furnished by mitochondria, minuscule living structures sitting inside our cells or dispatched back and forth within them to where they are needed. Mitochondria produce energy by burning down what remains of our meal after we have digested it, but at the cost of constantly corroding themselves and us. Here we review how our mitochondria evolved from invading bacteria and have retained a small amount of independence from us; how we inherit them only from our mother; and how they are heavily implicated in learning, memory, cognition, and virtually every mental or neurological affliction. We discuss why counteracting mitochondrial corrosion with antioxidant supplements is often unwise, and why our mitochondria, and therefore we ourselves, benefit instead from exercise, meditation, sleep, sunshine, and particular eating habits. Finally, we describe how malfunctioning mitochondria force rats to become socially subordinate to others, how such disparity can be evened off by a vitamin, and why these findings are relevant to us.

Uniting the neurodevelopmental and immunological hypotheses: Neuregulin 1 receptor ErbB and Toll-like receptor activation in first-episode schizophrenia

Current pathophysiological models of schizophrenia focus on neurodevelopmental and immunological mechanisms. We investigated a molecular pathway traditionally linked to the neurodevelopmental hypothesis (neuregulin 1 - ErbB), and pathogen-associated pattern recognition receptors associated with the immune hypothesis (Toll-like receptors, TLRs). We recruited 42 first-episode, drug-naïve patients with schizophrenia and 42 matched healthy control subjects. In monocytes TLR4/TLR5 and ErbB expressions were measured with flow-cytometry. Pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and the anti-inflammatory cytokine IL-10 were determined following the stimulation of TLR4/TLR5 and ErbB. Results revealed increased TLR4/TLR5 and decreased ErbB4 expression in schizophrenia relative to the control subjects. The expression of ErbB2 and ErbB3 receptors was unaltered in schizophrenia. TLR4 stimulation resulted in lower pro-inflammatory cytokine production in schizophrenia compared to the control levels, whereas the stimulation of ErbB by neuregulin 1 led to higher pro-inflammatory cytokine levels in patients with schizophrenia relative to the control group. In healthy controls, ErbB activation was associated with a marked production of IL-10, which was dampened in schizophrenia. These results indicate that the stimulation of TLR4 and ErbB induces opposite pro-inflammatory cytokine responses in schizophrenia.

Plasma levels of Th17-related cytokines and complement C3 correlated with aggressive behavior in patients with schizophrenia

Increasing evidence indicates that immune inflammatory processes, especially autoimmune reaction, should be considered in the pathophysiology of schizophrenia and aggressive behavior. The present study aimed to explore the correlation between immune factors (C3 and Th17-related cytokines) and aggressive behavior in schizophrenia patients. Forty schizophrenia patients and forty age- and gender-matched healthy controls participated in the study. Blood samples were assessed by ELISA upon enrollment. Positive and negative syndrome scale (PANSS) and modified overt aggression scale (MOAS) were used to estimate the severity and aggressive symptoms of schizophrenia patients. Plasma levels of IL-17, IL-23, and TGF-β1 in schizophrenia patients were significantly higher than those in healthy controls [(37.63±17.82) vs. (29.34±10.38)pg/ml, p=0.02; (101.40±135.26) vs. (13.09±5.94) pg/ml, p=0.01; (2864.57±2163.61) vs. (1839.69±1797.73)pg/ml, p=0.04], whereas C3 levels were significantly lower in schizophrenia patients [( 120,479.67± 65,612.50) vs. ( 208,060.21± 217,008.21)ng/ml, p=0.02]. IL-17, IL-23, and TGF-β1 levels were positively related to total scores of MOAS (p=0.02, p=0.02 and p=0.03, respectively) and PANSS (p=0.04, p=0.04 and p=0.02, respectively), whereas C3 levels were negatively related to total PANSS scores (p=0.03). IL-17 and IL-23 levels were positively correlated with PANSS excited component scores (p=0.04 and p=0.01, respectively). Our findings suggested that the Th17-related cytokine levels were positively related to the severity of schizophrenia and aggressive behavior, whereas C3 levels were negatively related to the severity of schizophrenia. This study demonstrated that elevated levels of Th17-related cytokines and decreased levels of C3 could be potential biomarkers for schizophrenia and aggressive behavior.

miR-181b-5p, miR-195-5p and miR-301a-3p are related with treatment resistance in schizophrenia

The aim of the study was to determine the differences between expression levels of certain miRNAs, as their association with schizophrenia has been well presented in the literature, and to investigate their relation to treatment resistance in schizophrenic patients. Three groups were formed: 1) treatment-resistant group, 2) treatment responsive group and 3) healthy control group. Expression levels of miRNAs from peripheric blood samples were determined by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). We investigated the roles of 29 schizophrenia-related miRNAs in schizophrenia treatment and their potentials to be considered as indicators. Among these miRNAs, only miR-181b-5p, miR-195-5p and miR-301a-3p expressions were found to be significantly different between the treatment-resistant group and the group responding well to the treatment. miRNAs may cause resistance by silencing the receptor genes of the drugs used for schizophrenia treatment. miR-181b-5p, miR-195-5p and miR-301a-3p may be candidate indicators that can be used to reveal resistance against schizophrenia treatment.

Integrative transcriptome network analysis of iPSC-derived neurons from schizophrenia and schizoaffective disorder patients with 22q11.2 deletion

BACKGROUND

Individuals with 22q11.2 Deletion Syndrome (22q11.2 DS) are a specific high-risk group for developing schizophrenia (SZ), schizoaffective disorder (SAD) and autism spectrum disorders (ASD). Several genes in the deleted region have been implicated in the development of SZ, e.g., PRODH and DGCR8. However, the mechanistic connection between these genes and the neuropsychiatric phenotype remains unclear. To elucidate the molecular consequences of 22q11.2 deletion in early neural development, we carried out RNA-seq analysis to investigate gene expression in early differentiating human neurons derived from induced pluripotent stem cells (iPSCs) of 22q11.2 DS SZ and SAD patients.

METHODS

Eight cases (ten iPSC-neuron samples in total including duplicate clones) and seven controls (nine in total including duplicate clones) were subjected to RNA sequencing. Using a systems level analysis, differentially expressed genes/gene-modules and pathway of interests were identified. Lastly, we related our findings from in vitro neuronal cultures to brain development by mapping differentially expressed genes to BrainSpan transcriptomes.

RESULTS

We observed ~2-fold reduction in expression of almost all genes in the 22q11.2 region in SZ (37 genes reached p-value < 0.05, 36 of which reached a false discovery rate < 0.05). Outside of the deleted region, 745 genes showed significant differences in expression between SZ and control neurons (p < 0.05). Function enrichment and network analysis of the differentially expressed genes uncovered converging evidence on abnormal expression in key functional pathways, such as apoptosis, cell cycle and survival, and MAPK signaling in the SZ and SAD samples. By leveraging transcriptome profiles of normal human brain tissues across human development into adulthood, we showed that the differentially expressed genes converge on a sub-network mediated by CDC45 and the cell cycle, which would be disrupted by the 22q11.2 deletion during embryonic brain development, and another sub-network modulated by PRODH, which could contribute to disruption of brain function during adolescence.

CONCLUSIONS

This study has provided evidence for disruption of potential molecular events in SZ patient with 22q11.2 deletion and related our findings from in vitro neuronal cultures to functional perturbations that can occur during brain development in SZ.

Chemokine gene variants in schizophrenia

Background Chemokines are known to play a major role in driving inflammation and immune responses in several neuroinflammatory diseases, including multiple sclerosis, Alzheimer's disease and Parkinson's disease. Inflammation has also been implicated in the pathogenesis of schizophrenia. Aim We aimed to investigate a potential link between chemokines and schizophrenia and analyze the role of MCP-1-A2518G, SDF-1-3'A, CCR5-delta32, CCR5-A55029G, CXCR4-C138T and CCR2-V64I gene polymorphisms in the Turkish population. Methods Genotyping was conducted by PCR-RFLP based on 140 patients and 123 unrelated healthy controls to show the relation between chemokine gene variants and schizophrenia risk. Results Frequencies of CCR5-A55029G A genotypes and CCR5-A55029G AG genotypes were found higher in patients than the controls and even also CCR2-V64I WT: CCR5-A55029G A and CCR2-V64I 64I: CCR5-A55029G A haplotypes significantly associated according to Bonferroni correction. However, no significant association was found for any of the other polymorphisms with the risk of schizophrenia. Conclusions Our findings suggest that CCR5-A55029G polymorphisms and CCR2-V64I WT: CCR5-A55029G A and CCR2-V64I 64I: CCR5-A55029G A haplotypes might have association with schizophrenia pathogenesis.

The known and missing links between Toxoplasma gondii and schizophrenia

Toxoplasma gondii, an intracellular protozoan parasite, has a striking predilection for infecting the Central Nervous System and has been linked to an increased incidence of a number of psychiatric diseases. Several in vitro and in vivo studies have shown that T. gondii infection can affect the structure, bioenergetics and function of brain cells, and alters several host cell processes, including dopaminergic, tryptophan-kynurenine, GABAergic, AKT1, Jak/STAT, and vasopressinergic pathways. These mechanisms underlying the neuropathology of latent toxoplasmosis seem to operate also in schizophrenia, supporting the link between the two disorders. Better understanding of the intricate parasite-neuroglial communications holds the key to unlocking the mystery of T. gondii-mediated schizophrenia and offers substantial prospects for the development of disease-modifying therapies.

Prenatal immune activation in mice blocks the effects of environmental enrichment on exploratory behavior and microglia density

Adverse environmental factors including prenatal maternal infection are capable of inducing long-lasting behavioral and neural alterations which can enhance the risk to develop schizophrenia. It is so far not clear whether supportive postnatal environments are able to modify such prenatally-induced alterations. In rodent models, environmental enrichment influences behavior and cognition, for instance by affecting endocrinologic, immunologic, and neuroplastic parameters. The current study was designed to elucidate the influence of postnatal environmental enrichment on schizophrenia-like behavioral alterations induced by prenatal polyI:C immune stimulation at gestational day 9 in mice. Adult offspring were tested for amphetamine-induced locomotion, social interaction, and problem-solving behavior as well as expression of dopamine D1 and D2 receptors and associated molecules, microglia density and adult neurogenesis. Prenatal polyI:C treatment resulted in increased dopamine sensitivity and dopamine D2 receptor expression in adult offspring which was not reversed by environmental enrichment. Prenatal immune activation prevented the effects of environmental enrichment which increased exploratory behavior and microglia density in NaCl treated mice. Problem-solving behavior as well as the number of immature neurons was affected by neither prenatal immune stimulation nor postnatal environmental enrichment. The behavioral and neural alterations that persist into adulthood could not generally be modified by environmental enrichment. This might be due to early neurodevelopmental disturbances which could not be rescued or compensated for at a later developmental stage.

Biomarkers for drug development in early psychosis: Current issues and promising directions

A major goal of current research in schizophrenia is to understand the biology underlying onset and early progression and to develop interventions that modify these processes. Biomarkers can play a critical role in identifying disease state, factors contributing to underlying progression, as well as predicting and monitoring response to treatment. Once biomarker-based therapeutics are established, biomarkers can guide treatment selection. It is increasingly clear that a wide range of potential biomarkers should be examined in schizophrenia, given the large number of genetic and environmental factors that have been identified as risk factors. New models for analysis of biomarkers are needed that represent the central nervous system as a highly complex, dynamic, and interactive system. Many tools are available with which to study relevant brain chemistry, but most are indirect measures and represent only a small fraction of the potential etiologic factors contributing to the molecular, structural and functional components of schizophrenia. This review represents the work of the International Society for CNS Clinical Trials and Methodology (ISCTM) Biomarkers Working Group. It discusses advantages and disadvantages of different categories of biomarkers and provides a summary of evidence that biomarkers representing inflammation, oxidative stress, endocannabinoids, glucocorticoid, and biogenic amines systems are dysregulated and potentially interactive in early phase schizophrenia. As has been recently demonstrated in several neurodevelopmental and neurodegenerative disorders, a multi-modal, longitudinal strategy involving a diverse array of biomarkers and new approaches to statistical modeling are needed to improve early interventions based on the fuller understanding.

Potential Etiologic Factors of Microbiome Disruption in Autism

PURPOSE

The primary purpose of this article was to consider the candidate disruptors of the development of a healthy microbiome in patients with autism. The reported abnormalities in the microbiome of individuals with autism are discussed.

METHODS

This selected review used data from published articles related to the assessment of microbiota in autism. Evidence-based support of factors known to affect the intestinal microbiome in individuals with autism are presented. Proposed interventions are evaluated and discussed.

FINDINGS

Studies that have investigated the intestinal microbiome in patients with autism have reported significant differences versus unaffected controls. Increased clostridial species in autism have been reported in several studies. These differences may have resulted from a number of environmental factors. Microbiome alterations that might contribute to the development of autism include altered immune function and bacterial metabolites.

IMPLICATIONS

Efforts to modify microbial imbalances through a variety of interventions are addressed. Focusing on mechanisms that drive imbalances in the microbiome may affect the development of disease. Altered intestinal health may contribute to the development of autistic behaviors or autism itself. Interventions aimed at improving intestinal health may favorably affect the microbiome and autism.

The association between antibodies to neurotropic pathogens and schizophrenia: a case-control study

Background:

Exposure to neurotropic pathogens has been proposed as an environmental risk factor for schizophrenia and can be evaluated by measuring pathogen-specific immunoglobulin G (IgG). Seroprevalence of pathogen-specific IgG reflects prior exposure, whereas IgG levels are associated with reactivity or reinfection. Several studies have examined these parameters in schizophrenia. However, results still remain inconclusive, as several previous studies did not correct for important confounding factors.

Aims:

To investigate whether schizophrenia is associated with prior exposure to neurotropic pathogens, or with their reactivation.

Methods:

We examined the seroprevalence and titer of IgG antibodies against herpes simplex virus-1 and -2 (HSV-1/HSV-2), varicella zoster virus (VZV), Epstein–Barr virus (EBV), cytomegalovirus (CMV), and Toxoplasma gondii (TG) in plasma of 368 adult patients with a schizophrenia spectrum disorder and 282 controls using ELISA.

Results:

We did not find evidence for an increased exposure to HSV-1, HSV-2, EBV, and TG in patients. There was a significantly higher seroprevalence of VZV (98.9% vs. 95.6%, P<0.05) and CMV (40.4% vs. 27.7%, P<0.001) in controls as compared with patients, which did not remain statistically significant after adjustment for various potential confounders. We did not find significant differences in antibody titers of seropositive patients and controls for any of the six pathogens.

Conclusions:

Our results do not support the hypothesis that increased exposure to neurotropic pathogens after birth is associated with schizophrenia.

Animal models of gene-environment interaction in schizophrenia: A dimensional perspective

Schizophrenia has long been considered as a disorder with multifactorial origins. Recent discoveries have advanced our understanding of the genetic architecture of the disease. However, even with the increase of identified risk variants, heritability estimates suggest an important contribution of non-genetic factors. Various environmental risk factors have been proposed to play a role in the etiopathogenesis of schizophrenia. These include season of birth, maternal infections, obstetric complications, adverse events at early childhood, and drug abuse. Despite the progress in identification of genetic and environmental risk factors, we still have a limited understanding of the mechanisms whereby gene-environment interactions (G × E) operate in schizophrenia and psychoses at large. In this review we provide a critical analysis of current animal models of G × E relevant to psychotic disorders and propose that dimensional perspective will advance our understanding of the complex mechanisms of these disorders.